The goal of this proposal is to characterize how the brain processes stimuli in order to produce adaptive behavioral responses. This objective is crucial for an understanding of how the brain controls both normal and maladaptive behaviors. This process will be studied in the honeybee olfactory system, a system that is functionally and structurally homologous to the mammalian olfactory system but is simpler and thus more amenable to a detailed mechanistic analysis. The general approach will be to use tetrodes to simultaneously record multiple neurons from the antennal lobes (ALs) of honeybees that are either naive or who have been trained using proboscis extension conditioning. The first Specific Aim of the proposal is to determine whether the population responses of AL neurons to various odors become decorrelated over time, a possible adaptation that could contribute to the ability to classify and identify a large number of odors. The second Specific Aim is to record from the ALs of conditioned animals, to determine whether population responses to odors that have been similarly rewarded diverge less than the responses to differentially reinforced odors. The third Specific Aim is to record from the ALs of honeybees as they are being conditioned, to characterize the timecourses of electrophysiological and behavioral changes. [unreadable] [unreadable]